Memory card authentication system, capacity switching-type memory card host device, capacity switching-type memory card, storage capacity setting method, and storage capacity setting program

ABSTRACT

A system for authenticating a memory card including: a capacity switching-type memory card host device including a capacity switch notification module which notifies a memory card targeted for exchanging information that the capacity switching-type memory card host device handles a capacity switching-type memory card, and a capacity switch authentication module which authenticates whether the targeted memory card is the capacity switching-type memory card; a capacity switching-type memory card including a capacity switching-type controller which flags the large-capacity expression register use flag on receipt of notification of being the capacity switching-type memory card host device; and a bus which transmits and receives data between the capacity switching-type memory card host device and the capacity switching-type memory card.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application P2002-245875 filed on Aug. 26, 2002;the entire contents of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a memory card authentication system, acapacity switching-type memory card host device, a capacityswitching-type memory card, a storage capacity setting method, and astorage capacity setting program, which are capable of adopting aconventional capacity expression with an internal register and a newcapacity expression and are capable of using a plurality of capacityexpressions while switching the capacity expressions.

2. Description of the Related Art

A memory card containing a rewritable nonvolatile memory, which does notlose information saved therein even if a power supply is turned off, isa storage device for saving digital information for a device forcontrolling the digital information, such as a digital camera, aportable music player or a personal digital assistance (such a devicewill be hereinafter referred to as a “memory card host device”). Such amemory card includes a register for indicating a storage capacity;however, the momentum of increases in memory size will soon surpass thecapacity which the register can express.

There are disclosed some technologies related to memory cards, such as arecording device which includes two memory cards in order to physicallyincrease a storage capacity (Japanese Patent Application Laid-open No.2001-325127).

It is necessary to consider a new method for expressing a storagecapacity in order to increase a capacity of a memory card. However, whena current register is simply replaced, such a capacity switching-typememory card cannot be used with a conventional memory card host device.

SUMMARY OF THE INVENTION

A first aspect of the present invention is to provide a system forauthenticating a memory card, comprising: a) a capacity switching-typememory card host device including a capacity switch notification modulewhich notifies a memory card targeted for exchanging information thatthe capacity switching-type memory card host device handles a capacityswitching-type memory card, and a capacity switch authentication modulewhich refers to a state of a large-capacity expression register use flagof the targeted memory card and authenticates whether the targetedmemory card is the capacity switching-type memory card; b) a capacityswitching-type memory card including a capacity switching-typecontroller which flags the large-capacity expression register use flagon receipt of notification of being the capacity switching-type memorycard host device, the large-capacity expression register use flagindicating use of a large-capacity expression register which retainsinformation with a capacity exceeding a capacity which can be expressedby an internal register; and c) a bus which transmits and receives databetween the capacity switching-type memory card host device and thecapacity switching-type memory card.

A second aspect of the present invention is to provide a host deviceexchanging information with a memory card in a memory cardauthentication system, the host device, comprising: a) a capacity switchnotification module which notifies a memory card targeted for exchanginginformation that the host device handles a capacity switching-typememory card; and b) a capacity switch authentication module which refersto a state of a large-capacity expression register use flag of thetargeted memory card and authenticates whether the targeted memory cardis the capacity switching-type memory card.

A third aspect of the present invention is to provide a memory card,comprising: a) a capacity switching-type internal storage elementincluding a plurality of storage areas, a master boot sector whichretains file information on each of the plurality of storage areas, aninternal register which retains capacity information on each of theplurality of storage areas, a large-capacity expression register whichretains information with a capacity exceeding a capacity which can beexpressed by the internal register, and a large-capacity expressionregister use flag which indicates use of the large-capacity expressionregister; and b) a capacity switching-type controller which flags thelarge-capacity expression register use flag upon notification that amemory card host device targeted for exchanging information is acapacity switching-type memory card host device capable of using aplurality of capacity expressions while switching between the capacityexpressions.

A forth aspect of the present invention is to provide a method forsetting a storage capacity in a host device exchanging information witha memory card, the method, comprising: a) initializing the memory card;b) obtaining information on an internal register of the memory card; c)judging whether the memory card can use a plurality of capacityexpressions while switching between the capacity expressions; d)authenticating a capacity expression of the internal register of thememory card when the memory card is incapable of using the plurality ofcapacity expressions by switching between the capacity expressions; ande) using a capacity expressed by the internal register.

A fifth aspect of the present invention is to provide a method forsetting a storage capacity in a host device exchanging information witha memory card, the method, comprising: a) initializing the memory card;b) obtaining information on an internal register of the memory card; c)judging whether the memory card can use a plurality of capacityexpressions while switching between the capacity expressions; d)authenticating a capacity expression of a large-capacity expressionregister of the memory card when the memory card can use the pluralityof capacity expressions by switching between the capacity expressions;and e) using a capacity expressed by the large-capacity expressionregister.

A sixth aspect of the present invention is to provide a storage capacitysetting computer program product to be executed by a host device, thehost device exchanging information with a memory card in a memory cardauthentication system, the computer program product, comprising: a)instructions for the host device to initialize the memory card; b)instructions for the host device to obtain information on an internalregister of the memory card; c) instructions for the host device tojudge whether the memory card can use a plurality of capacityexpressions while switching between the capacity expressions; d)instructions for the host device to authenticate a capacity expressionof the internal register of the memory card when the memory card isincapable of using the plurality of capacity expressions by switchingbetween the capacity expressions; and e) instructions for the hostdevice to use a capacity expressed by the internal register.

A seventh aspect of the present invention is to provide a storagecapacity setting computer program product to be executed by a hostdevice, the host device exchanging information with a memory card in amemory card authentication system, the computer program product,comprising procedures for: a) instructions for the host device toinitialize the memory card; b) instructions for the host device toobtain information on an internal register of the memory card; c)instructions for the host device to judge whether the memory card canuse a plurality of capacity expressions while switching between thecapacity expressions; d) instructions for the host device toauthenticate a capacity expression of a large-capacity expressionregister of the memory card when the memory card can use the pluralityof capacity expressions by switching between the capacity expressions;and e) instructions for the host device to use a capacity expressed bythe large-capacity expression register.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a configuration of a memory cardauthentication system according to the embodiment of the presentinvention.

FIG. 2 is a flowchart showing a storage capacity setting methodaccording to the embodiment of the present invention.

FIG. 3 is a schematic view showing a state of a capacity switching-typememory card according to the embodiment of the present invention, whichis used in combination with a conventional memory card host device.

FIG. 4 is a schematic view showing a state of the capacityswitching-type memory card according to the embodiment of the presentinvention, which is used in combination with a capacity switching-typememory card host device.

FIG. 5 is a block diagram showing a configuration of a capacityswitching-type controller of the capacity switching-type memory cardaccording to the embodiment of the present invention.

FIG. 6 is a view showing an example of a method of qualifying aplurality of partitions as a single partition.

FIG. 7 is a view showing another example of a method of qualifying aplurality of partitions as a single partition.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of the present invention will be described withreference to the accompanying drawings. It is to be noted that the sameor similar reference numerals are applied to the same or similar partsand elements throughout the drawings, and the description of the same orsimilar parts and elements will be omitted or simplified.

As shown in FIG. 1, a memory card authentication system according to theembodiment of the present invention includes a host device group 1having two types of memory card host devices which are a capacityswitching-type memory card host device 12 and a conventional memory cardhost device 13; a memory card group 3 which exchanges information withthe host device group 1; and a bus 2 for transmitting and receiving databetween the host device group 1 and the memory card group 3.

The capacity switching-type memory card host device 12 includes acapacity switch notification module 14 which notifies to a memory cardtargeted for information exchange that the capacity switching-typememory card host device handles a capacity switching-type memory carddesigned to switch a plurality of capacity expressions, and a capacityswitch authentication module 15 which refers to a state of alarge-capacity expression register use flag 166 of the targeted memorycard and thereby authenticates whether or not the targeted memory cardis the capacity switching-type memory card 32. Here, the “capacityexpression” refers to a method of expressing a capacity of a storagearea which the memory card has. The capacity switching-type memory cardhost device 12 includes a central processing unit (CPU), and may adoptsuch a configuration as to incorporate the capacity switch notificationmodule 14, the capacity switch authentication module 15. These modulescan be realized by executing a dedicated program for utilizing a givenprogramming language. Moreover, the capacity switching-type memory cardhost device 12 may include a program storage device 20 which saves astorage capacity setting program for causing the capacity switchnotification module 14 and the like to execute functions thereof. It ispossible to allow the capacity switching-type memory card host device 12to execute a procedure for obtaining information on an internal registerof the memory card and a procedure for authenticating the register ofthe memory card by means of reading the storage capacity setting programfrom the program storage device 20. The program storage device 20 may bean internal storage device such as a random access memory (RAM), or anexternal storage device such as a hard disk (HD) or a flexible disk(FD). It is easy to save, carry and sell a program by use of the storagedevice which saves the above-described program. Specifically, the memorycard host device to be included in the host device group 1 may be adigital camera, a portable music player, a personal digital assistance,a car navigation system, a cellular telephone, a silicon audio player,an electronic dictionary, or the like.

The capacity switching-type memory card host device 12 according to theembodiment of the present invention adopts a capacity expression by aconventional internal register and a new capacity expression, and uses aplurality of the capacity expressions while switching between thecapacity expressions. Thus, the capacity switching-type memory card hostdevice 12 can handle a plurality of memory cards with differentcharacteristics. Moreover, since the capacity switching-type memory cardhost device 12 can handle both the capacity switching-type memory card32 and a conventional memory card 33, the capacity switching-type memorycard host device 12 can maintain compatibility.

The memory card group 3 includes two types of memory cards, the capacityswitching-type memory card 32 of the present invention and theconventional memory card 33.

The conventional memory card 33 includes at least a fixed capacity-typeinternal storage element 17 and a controller 19. The fixed capacity-typeinternal storage element 17 includes a master boot sector 171 whichretains single partition information, a single partition 172 which is astorage area, and an internal register 173 which retains storagecapacity information. The single partition information, which is theinformation on the single partition 172, is retained in the master bootsector 171. In FIG. 1, since the single partition 172 applies the FAT 16file system, a partition type thereof is described as 06h. Thecontroller 19 receives a command and data to the memory card group 3from a particular memory card host device in the host device group 1through the bus 2, and controls the storage area based on the commandand the data. Moreover, the controller 19 also responds to the commandfrom the particular memory card host device in the host device group 1and transmits data.

The capacity switching-type memory card 32 includes a capacityswitching-type internal storage element 16 and a capacity switching-typecontroller 18. The capacity switching-type internal storage element 16includes a master boot sector 161 which retains first and secondpartition information, a first partition 162 which is a first storagearea, a second partition 163 which is a second storage area, an internalregister 164 which retains storage capacity information, alarge-capacity expression internal register 165 which retainsinformation with a capacity exceeding a capacity that can be expressedby the internal register, and the large-capacity expression register useflag 166 which indicates that the large-capacity expression internalregister 165 is being used. In FIG. 1, since the first partition 162applies the FAT 16 file system, a partition type thereof is described as06h. Meanwhile, since the second partition 163 applies the FAT 32 filesystem, a partition type thereof is described as 0Bh. The capacityswitching-type controller 18 receives a command and data to the capacityswitching-type memory card 32 from a particular memory card host devicein the host device group 1 through the bus 2, and controls the storageareas based on the command and the data. Moreover, the capacityswitching-type controller 18 also responds to the command from theparticular memory card host device in the host device group 1 andtransmits data. Furthermore, the capacity switching-type controller 18flags the large-capacity expression register use flag 166 on receipt ofnotification that the particular host device is the capacityswitching-type memory card host device 12. In addition, when thecapacity switching-type controller 18 is used in combination with theconventional memory card host device 13, the capacity switching-typecontroller 18 changes the information on a partition which is retainedin the master boot sector 161 and might be (or can be) authenticated bythe conventional memory card host device 13, in a manner of hiding theinformation from the conventional memory card host device 13. Thischanging function will be described later in detail.

The memory card included in the memory card group 3 specifically hasdimensions of 24×32×2.1 mm and a copyright protection function compliantwith the secure digital music initiative (SDMI) standard. The memorycard is, for example, a secure digital (SD) memory card, which has uppercompatibility with a multimedia card (MMC). The SD memory card is amemory card, based on the SDMI standard, which has been jointlydeveloped by Toshiba Corporation, Matsushita Electric Industrial Co.,Ltd., and SanDisk Corporation. In the SD memory card, the internalregister is referred to as a CSD register. The SD memory card basicallyapplies the FAT 16 file system which is defined by ISO/IEC 9293.

The capacity switching-type memory card 32 of the present inventionadopts the capacity expression by the conventional internal register andthe new capacity expression, and uses the plurality of capacityexpressions while switching between the capacity expressions. In thisway, it is possible to handle a large capacity. Moreover, the capacityswitching-type memory card 32 of the present invention can be handled byboth the capacity switching-type memory card host device 12 and theconventional memory card host device 13. Accordingly, the capacityswitching-type memory card 32 can maintain compatibility.

As shown in FIG. 1, the memory card authentication system according tothe embodiment of the present invention can be applied to anycombination of the capacity switching-type memory card host device 12and the capacity switching-type memory card 32; the capacityswitching-type memory card host device 12 and the conventional memorycard 33; and the conventional memory card host device 13 and thecapacity switching-type memory card 32.

Next, a storage capacity setting method for a memory card host deviceaccording to the embodiment of the present invention will be describedby use of FIGS. 1 and 2.

a) First, in Step S101 in FIG. 2, a particular memory card host devicein the host device group 1 issues an initialization command and therebyinitializes a particular memory card in the memory card group 3. Whenthe particular memory card host device is the capacity switching-typememory card host device 12, the capacity switch notification module 14notifies the particular memory card that the particular memory card hostdevice is the capacity switching-type memory card host device 12 as anargument of the initialization command. For example, the initializationcommand to the SD memory card consists of a command length of 48 bits, 6bits of which are used for the contents of the command, and 32 bits ofwhich are used for the argument. The information that the particularmemory card host device is the capacity switching-type memory card hostdevice 12 may use an unused area in the 32-bit argument. When theparticular memory card, which receives the notification that theparticular memory card host device is the capacity switching-type memorycard host device 12, is the capacity switching-type memory card 32, thecapacity switching-type controller 18 of the capacity switching-typememory card 32 flags the large-capacity expression register use flag166. The initialization command used in Step S101 may apply a commandwhich has already been applied to the SD memory card or the like.Alternatively, it is also possible to add a new command.

b) Next, in Step S102, the particular memory card host device in thehost device group 1 obtains a card ID, such as a serial number or a dateof manufacture, of the particular memory card in the memory card group3. Thereafter, in Step S103, the particular memory card host deviceobtains a card address. The card address is used for identifying thepositions of a plurality of memory cards when the plurality of memorycards are inserted in the memory card host device, for example.

c) Next, in Step S104, the particular memory card host device in thehost device group 1 issues an internal register information retrievalcommand to recognize the capacity of the particular memory card in thememory card group 3. When the particular memory card is the capacityswitching-type memory card 32, the capacity switching-type controller 18of the capacity switching-type memory card 32 notifies the state of thelarge-capacity expression register use flag 166 to the memory card hostdevice as part of a response to the information retrieval command. Inthe case of the SD card, for example, of the response to the informationretrieval command, 6 bits are used for the contents of the command and127 bits or 32 bits are used for an argument. The state of thelarge-capacity expression register use flag 166 may use an unused areain the 127-bit or 32-bit argument. When the memory card host device isthe capacity switching-type memory card host device 12, the capacityswitch authentication module 15 of the capacity switching-type memorycard host device 12 refers to the state of the large-capacity expressionregister use flag 166 and thereby authenticates that the particularmemory card is the capacity switching-type memory card 32. When theparticular memory card host device is the conventional memory card hostdevice 13, the particular memory card host device naturally cannot referto the large-capacity expression register use flag 166. The informationretrieval command used in Step S104 may apply a command which has beenalready applied to the SD memory card or the like. Alternatively, it isalso possible to add a new command.

d) Next, in Step S105, a judgment is made as to whether or not theparticular memory card in the memory card group 3 is the capacityswitching-type memory card 32. When the particular memory card is theconventional memory card 33, the response to the internal registerinformation retrieval command shows a state that the large-capacityexpression register use flag 166 is not flagged. Accordingly, thecapacity switching-type memory card host device 12 can judge whether theparticular memory card is the capacity switching-type memory card 32. Inthe case of the conventional memory card host device 13, every memorycard is authenticated as the conventional memory card 33 because theconventional memory card host device 13 cannot refer to thelarge-capacity expression register use flag 166.

e) When the judgment is made as “corresponding to capacity switch” inStep S105, in other words, when the particular memory card host devicein the host device group 1 is the capacity switching-type memory cardhost device 12 and the particular memory card in the memory card group 3is the capacity switching-type memory card 32, the process advances toStep S111. The capacity switching-type memory card host device 12 thenreads the large-capacity expression register 165 from the capacityswitching-type memory card 32. Next, in Step S112, the capacityswitching-type memory card host device 12 reads the master boot sector161. Thereafter, in Step S113, the capacity switching-type memory cardhost device 12 authenticates that the first partition 162 and the secondpartition 163 exist in the capacity switching-type memory card 32 by useof the first partition information and the second partition information.

f) Next, in Step S114, the capacity switching-type memory card hostdevice 12 performs a setting to make the first partition 162 and thesecond partition 163 accessible as a single partition. User access isfacilitated by qualifying the first partition 162 and the secondpartition 163 collectively as the single partition. Concrete examples ofthe method for setting of the single partition are shown in FIG. 6 andFIG. 7. FIG. 6 shows a method of logically connecting three partitionsof C: 801, D: 802, and E: 803 and thereby qualifying these threepartitions collectively as a single partition C′: 804. FIG. 7 shows amethod applied to two partitions of C: 901 and D: 902, in which C: 901is qualified as a file D:/Part 1903 included in D: 902, so as to makethe two partitions accessible as a single partition. Access isfacilitated by these methods. Next, in Step S115, the capacityswitching-type memory card host device 12 sets the capacity expressed bythe large-capacity expression register 165 usable, and the capacitysetting process is completed in Step S110.

g) If the judgment is made as being “not corresponding to capacityswitch” in Step S105, the combination is any of the following threecombinations: the conventional memory card host device 13 and thecapacity switching-type memory card 32; the capacity switching-typememory card host device 12 and the conventional memory card 33; and theconventional memory card host device 13 and the conventional memory card33. The combination of the conventional memory card host device 13 andthe conventional memory card 33 represents a conventional operation.Accordingly, description thereof will be omitted.

In the case of the combination of the conventional memory card hostdevice 13 and the capacity switching-type memory card 32, the processadvances to Step S106. The conventional memory card host device 13authenticates every card as the conventional memory card 33 because theconventional memory card host device 13 cannot refer to thelarge-capacity expression register use flag 166 included in the responseto the internal register information retrieval command received in StepS104. Therefore, in Step S106, the capacity expression of the internalregister 164 is authenticated. The conventional memory card host device13 reads the internal register 164 out of the capacity switching-typememory card 32. Next, in Step S107, the conventional memory card hostdevice 13 reads the master boot sector 161. Here, in Step S108, thecapacity switching-type controller 18 of the capacity switching-typememory card 32 modifies the second partition information in the masterboot sector 161 and transmits the information so that the conventionalmemory card host device 13 recognizes the existence of only the firstpartition 162. The method for modifying the second partition informationwill be described later in detail together with the detail of thecapacity switching-type controller 18. In Step S109, the conventionalmemory card host device 13 sets the capacity expressed by the internalregister 164 as usable, and the capacity setting process is completed inStep S110.

In the case of the combination of the capacity switching-type memorycard host device 12 and the conventional memory card, the processadvances to Step S106. The capacity switching-type memory card hostdevice 12 refers to the fact that the large-capacity expression registeruse flag 166 is not flagged from the response to the internal registerinformation retrieval command received in Step S104, and therebyauthenticates the memory card as being a conventional memory card 33.Accordingly, the capacity switching-type memory card host device 12authenticates the capacity expression of the internal register 173 inStep S106. Next, in Step S107, the capacity switching-type memory cardhost device 12 reads the master boot sector 171. In Step S108, thecapacity switching-type memory card host device 12 authenticates thesingle partition 172 from the single partition information. Thereafter,in Step S109, the capacity switching-type memory card host device 12sets the capacity expressed by the internal register 173 as usable, andthe capacity setting process is completed in Step S110.

Here, description will be made regarding a mechanism that the capacityswitching-type memory card 32 causes the conventional memory card hostdevice 13 not to authenticate the second partition information in themaster boot sector 161 in the case of the combination of theconventional memory card host device 13 and the capacity switching-typememory card 32. This mechanism is applied to the process in Step S108.

As shown in FIG. 5, the capacity switching-type controller 18 of thecapacity switching-type memory card 32 includes an interface 78 whichconnects the memory card host device to the capacity switching-typeinternal storage element 16, a comparator 76 connected to the interface78, and a selector 75 connected to the comparator 76. The interface 78is connected to the capacity switching-type internal storage element 16through an address bus 73. The comparator 76 receives an accessdestination to the capacity switching-type internal storage element 16from the interface 78. The selector 75 selects any of output data 74from the capacity switching-type internal storage element 16 andpartition information 72 which cannot be authenticated by theconventional memory card host device 13, based on information from thecomparator 76 and the state of the large-capacity expression registeruse flag 166. Then, the selector 75 transmits the selected one to theinterface 78.

The condition that the selector 75 selects the unauthenticatablepartition information 72 occurs when a condition of the comparatorconnected to the address bus 73 is satisfied and the large-capacityexpression register use flag 166 is not used at the same time. Thecondition to satisfy the comparator 76 is when there is access to thecapacity switching-type internal storage element 16 to obtain the secondpartition information in the master boot selector 161, for example. Inthis way, when the conventional memory card host device 13 tries toobtain the second partition information, the unauthenticatable partitioninformation 72 will be transmitted to the interface 78. Accordingly, theconventional memory card host device 13 cannot authenticate theexistence of the second partition 163 from the second partitioninformation. Upon access other than the access to obtain the secondpartition information, the output data 74 of the capacity switching-typeinternal storage element 16 is outputted to the interface 78. Therefore,there is no influence on the data other than the second partitioninformation.

FIG. 3 shows a state of the capacity switching-type internal storageelement 16 of the capacity switching-type memory card 32 when thecapacity switching-type memory card 32 is used in combination with theconventional memory card host device 13. The partition type whichconstitutes the “unauthenticatable second partition information” in themaster boot sector 161 is not the original “0Bh” (FAT 32). Instead ofthis, the type “1Bh” (hidden FAT 32), for example, is selected by theselector 75. In this way, the second partition information isauthenticated as the “1Bh” by the conventional memory card host device13, and the second partition 163 is not authenticated by theconventional memory card host device 13. Meanwhile, the internalregister 164 is used as the register for indicating the capacity, andthe large-capacity expression register 165 and the large-capacityexpression register use flag 166 are not used.

On the other hand, FIG. 4 shows a state of the capacity switching-typeinternal storage element 16 of the capacity switching-type memory card32 when the capacity switching-type memory card 32 is used incombination with the capacity switching-type memory card host device 12.The first partition information and the second partition information inthe master boot sector 161 are transmitted to the capacityswitching-type memory card host device 12 without modification.Accordingly, the first partition 162 and the second partition 163 areauthenticated by the capacity switching-type memory card host device 12.The large-capacity expression register 165 is used as the registerindicating the capacity, and the capacity information in the internalregister 164 is not used. Meanwhile, the large-capacity expressionregister use flag 166 is used.

The storage capacity setting method according to the embodiment of thepresent invention adopts the capacity expression by the conventionalinternal register and the new capacity expression, and uses theplurality of capacity expressions while switching between the capacityexpressions. Moreover, according to the storage capacity setting methodaccording to the embodiment of the present invention, the host devicegroup 1 and the memory card group 3 can operate without problems andmaintain compatibility in any combination of: the capacityswitching-type memory card host device 12 and the capacityswitching-type memory card 32; the capacity switching-type memory cardhost device 12 and the conventional memory card 33; and the conventionalmemory card host device 13 and the capacity switching-type memory card32.

According to the embodiment of the present invention, it is possible toprovide the memory card authentication system, the capacityswitching-type memory card host device, the capacity switching-typememory card, the storage capacity setting method, and the storagecapacity setting program, which can adopt the capacity expression by theconventional internal register and the new capacity expression, and makeuse of the plurality of capacity expressions while switching between thecapacity expressions.

(Other Embodiments)

Although the present invention has been described above with referenceto the embodiment, it is to be understood that the present inventionshall not be limited to the descriptions and the drawings whichconstitute part of this disclosure. It is obvious to those skilled inthe art that various modifications, alterations, and improvements becomepossible from the teachings of this disclosure.

For example, the capacity switching-type memory card 32 according to theembodiment of the present invention has been described with the drawingswhich include the two partitions (storage areas) 162 and 163. However,needless to say, the memory card 32 may include more than twopartitions. In such a case, information on each of the partitions willbe saved in the master boot sector 161.

Various modifications will become possible for those skilled in the artafter receiving the teachings of the present disclosure withoutdeparting from the scope thereof

1. A system for authenticating a memory card, the system, comprising: acapacity switching-type memory card host device including a capacityswitch notification module which notifies a memory card targeted forexchanging information that the capacity switching-type memory card hostdevice handles a capacity switching-type memory card, and a capacityswitch authentication module which refers to a state of a large-capacityexpression register use flag of the targeted memory card andauthenticates whether the targeted memory card is the capacityswitching-type memory card; a capacity switching-type memory cardincluding a capacity switching-type controller which flags thelarge-capacity expression register use flag on receipt of notificationof being the capacity switching-type memory card host device, thelarge-capacity expression register use flag indicating use of alarge-capacity expression register which retains information with acapacity exceeding a capacity which can be expressed by an internalregister; and a bus which transmits and receives data between thecapacity switching-type memory card host device and the capacityswitching-type memory card.
 2. A host device exchanging information witha memory card in a memory card authentication system, the host device,comprising: a capacity switch notification module which notifies amemory card targeted for exchanging information that the host devicehandles a capacity switching-type memory card; and a capacity switchauthentication module which refers to a state of a large-capacityexpression register use flag of the targeted memory card andauthenticates whether the targeted memory card is the capacityswitching-type memory card.
 3. The host device of claim 2, wherein thecapacity switch notification module notifies the targeted memory cardthat the host device handles the capacity switching-type memory card, aspart of an argument of an initialization command.
 4. The host device ofclaim 3, wherein the argument of the initialization command includes 32bits.
 5. The host device of claim 2, wherein the capacity switchauthentication module refers to the state of the large-capacityexpression register use flag from part of an argument of a response toan internal register information retrieval command of the targetedmemory card.
 6. The host device of claim 5, wherein the argument of theresponse to the internal register information retrieval command includesany of 127 bits and 32 bits.
 7. A memory card, comprising: a capacityswitching-type internal storage element including a plurality of storageareas, a master boot sector which retains file information on each ofthe plurality of storage areas, an internal register which retainscapacity information on each of the plurality of storage areas, alarge-capacity expression register which retains information with acapacity exceeding a capacity which can be expressed by the internalregister, and a large-capacity expression register use flag whichindicates use of the large-capacity expression register; and a capacityswitching-type controller which flags the large-capacity expressionregister use flag upon notification that a memory card host devicetargeted for exchanging information is a capacity switching-type memorycard host device capable of using a plurality of capacity expressionswhile switching between the capacity expressions.
 8. The memory card ofclaim 7, wherein the capacity switching-type controller receivesnotification of being the capacity switching-type memory card hostdevice, as part of an argument of an initialization command.
 9. Thememory card of claim 8, wherein the argument of the initializationcommand includes 32 bits.
 10. The memory card of claim 7, wherein thecapacity switching-type controller notifies a state of thelarge-capacity expression register use flag to the capacityswitching-type memory card host device as part of an argument of aresponse to an internal register information retrieval command.
 11. Thememory card of claim 10, wherein the argument of the response to theinternal register information retrieval command includes any of 127 bitsand 32 bits.
 12. The memory card of claim 7, wherein the capacityswitching-type controller comprises: an interface connected to thecapacity switching-type internal storage element through an address bus;a comparator which receives an access destination to the capacityswitching-type internal storage element from the interface; and aselector which selects any of output data from the capacityswitching-type internal storage element and partition information whichcannot be authenticated by a conventional memory card host device, basedon information from the comparator and on a state of the large-capacityexpression register use flag, and transmits any of the data and theinformation thus selected to the interface.
 13. The memory card of claim7, wherein the memory card has dimensions of 24×32×2.1 mm and includes acopyright protection function compliant with the secure digital musicinitiative standard.
 14. A method for setting a storage capacity in ahost device exchanging information with a memory card, the method,comprising: initializing the memory card; obtaining information on aninternal register of the memory card; judging whether the memory cardcan use a plurality of capacity expressions while switching between thecapacity expressions; authenticating a capacity expression of theinternal register of the memory card when the memory card is incapableof using the plurality of capacity expressions by switching between thecapacity expressions; and using a capacity expressed by the internalregister.
 15. A method for setting a storage capacity in a host deviceexchanging information with a memory card, the method, comprising:initializing the memory card; obtaining information on an internalregister of the memory card; judging whether the memory card can use aplurality of capacity expressions while switching between the capacityexpressions; authenticating a capacity expression of a large-capacityexpression register of the memory card when the memory card can use theplurality of capacity expressions by switching between the capacityexpressions; and using a capacity expressed by the large-capacityexpression register.
 16. The method of claim 15, further comprising:setting a plurality of storage areas accessible as a single storagearea.
 17. The method of claim 14 or 15, wherein the step of initializingincludes notifying the memory card that the host device handles acapacity switching-type memory card, which is capable of using theplurality of capacity expressions while switching between the capacityexpressions, as part of an argument of an initialization command. 18.The method of claim 17, wherein the argument of the initializationcommand includes 32 bits.
 19. The method of claim 14 or 15, wherein thestep of judging includes performing a judgment with reference to a stateof a large-capacity expression register use flag of the memory card, thestate being notified as part of an argument of a response to an internalregister information retrieval command.
 20. The method of claim 19,wherein the argument of the response to the internal registerinformation retrieval command includes any of 127 bits and 32 bits. 21.A storage capacity setting computer program product to be executed by ahost device, the host device exchanging information with a memory cardin a memory card authentication system, the computer program product,comprising: instructions for the host device to initialize the memorycard; instructions for the host device to obtain information on aninternal register of the memory card; instructions for the host deviceto judge whether the memory card can use a plurality of capacityexpressions while switching between the capacity expressions;instructions for the host device to authenticate a capacity expressionof the internal register of the memory card when the memory card isincapable of using the plurality of capacity expressions by switchingbetween the capacity expressions; and instructions for the host deviceto use a capacity expressed by the internal register.
 22. A storagecapacity setting computer program product to be executed by a hostdevice, the host device exchanging information with a memory card in amemory card authentication system, the computer program product,comprising procedures for: instructions for the host device toinitialize the memory card; instructions for the host device to obtaininformation on an internal register of the memory card; instructions forthe host device to judge whether the memory card can use a plurality ofcapacity expressions while switching between the capacity expressions;instructions for the host device to authenticate a capacity expressionof a large-capacity expression register of the memory card when thememory card can use the plurality of capacity expressions by switchingbetween the capacity expressions; and instructions for the host deviceto use a capacity expressed by the large-capacity expression register.